I will offer a counter-example to tptacek's argument:
For 18 months (till April) I lived at 16 Waverly Avenue in Brooklyn, New York. I never signed a lease. The landlord did not care about a thing, so long as I paid the rent on the time. In that building, sub-letting apartments is common. The landlord is an older Hasidic Jewish gentleman, and his attitude toward renters is fairly common among the Jewish landlords who own a large chunk of the southern Williamsburg neighborhood. In all of these buildings, the tendency is toward laissez faire. This cuts both ways: the landlord lets you do anything, but the landlord rarely fixes anything that you need fixed. For a particular type of person (like me) this seems like a reasonable trade-off. And in such circumstances, it is perfectly reasonable for renters to find sub-letters.
For 18 months (till April) I lived at 16 Waverly Avenue in Brooklyn, New York. I never signed a lease. The landlord did not care about a thing, so long as I paid the rent on the time. In that building, sub-letting apartments is common. The landlord is an older Hasidic Jewish gentleman, and his attitude toward renters is fairly common among the Jewish landlords who own a large chunk of the southern Williamsburg neighborhood. In all of these buildings, the tendency is toward laissez faire. This cuts both ways: the landlord lets you do anything, but the landlord rarely fixes anything that you need fixed. For a particular type of person (like me) this seems like a reasonable trade-off. And in such circumstances, it is perfectly reasonable for renters to find sub-letters.